Systems and methods for reducing coke formation of fuel supply systems

Abstract

A fuel supply system includes a first component configured to direct a fuel flow to a combustor of an engine system. The first component includes a first inner surface and a first outer surface. The fuel supply system also includes an outer coating disposed on the first outer surface of the first component. The outer coating is configured to thermally insulate a first interior of the first component to reduce non-catalytic coke formation in the first interior. Additionally, the fuel supply system includes an inner coating disposed on the first inner surface of the first component. The inner coating is configured to reduce the fuel flow from contacting a base material of the first inner surface of the first component to reduce catalytic coke formation in the first interior.

The invention claimed is: 
     
       1. A fuel supply system comprising:
 a first component configured to direct a fuel flow to a combustor of an engine system, wherein the first component is made of a metal, and the first component comprises a first inner surface and a first outer surface; 
 a first outer coating disposed on the first outer surface of the first component, wherein the first outer coating comprises a first thickness and is configured to thermally insulate a first interior of the first component to reduce non-catalytic coke formation in the first interior; and 
 a first inner coating disposed on the first inner surface of the first component, wherein the first inner coating comprises a second thickness and is configured to reduce contact of the fuel flow with the metal of the first inner surface of the first component to reduce catalytic coke formation in the first interior, wherein the first thickness is greater than the second thickness, wherein the first thickness and the second thickness each comprise a common coating material extending entirely therethrough along a radial direction, wherein a component thickness of the first component is greater than the first thickness and greater than the second thickness, and wherein the first outer coating comprises one or more layers each having a thickness of 1 mm to 10 mm to define the first thickness of the first outer coating. 
 
     
     
       2. The fuel supply system of  claim 1 , wherein the first component comprises a fuel conduit or a liquid fuel nozzle. 
     
     
       3. The fuel supply system of  claim 2 , wherein the fuel supply system comprises a second component configured to direct the fuel flow to the combustor, wherein the second component comprises a second inner surface and a second outer surface, a second outer coating is disposed on the second outer surface, and a second inner coating is disposed on the second inner surface. 
     
     
       4. The fuel supply system of  claim 3 , wherein the second component comprises a three-way valve, a liquid fuel check valve, or a mixing valve. 
     
     
       5. The fuel supply system of  claim 1 , excluding a recirculation system or a purging system, or any combination thereof. 
     
     
       6. The fuel supply system of  claim 1 , wherein the one or more layers of the first outer coating comprises a plurality of layers of the common coating material collectively defining the first thickness. 
     
     
       7. The fuel supply system of  claim 1 , wherein the common coating material comprises a RLHY-12 thermal barrier coating material. 
     
     
       8. The fuel supply system of  claim 1 , wherein the common coating material comprises a thermal barrier coating having a thermal conductivity value equal to or less than 0.03 watts per meter-kelvin (W·m −1 ·K −1 ). 
     
     
       9. The fuel supply system of  claim 1 , excluding a recirculation system and a purging system, wherein the engine system comprises a gas turbine system. 
     
     
       10. A fuel supply system comprising:
 a plurality of components configured to direct a fuel flow to a combustor of an engine system, wherein each component of the plurality of components is made of a metal and comprises a respective inner surface, a respective outer surface, and a respective interior; 
 a plurality of respective outer coatings, wherein each respective outer coating is disposed on the respective outer surface of a respective component of the plurality of components, and wherein each respective outer coating is configured to thermally insulate the respective interior of the respective component to reduce non-catalytic coke formation within the respective interior; and 
 a plurality of respective inner coatings, wherein each respective inner coating is disposed on the respective inner surface of the respective component of the plurality of components, wherein each respective inner coating is configured to reduce contact of the fuel flow with a respective metal of the respective inner surface of each component of the plurality of components to reduce catalytic coke formation in the respective interior; 
 wherein, on at least one component of the plurality of components, the respective outer coating of the plurality of respective outer coatings comprises a first thickness that is greater than a second thickness of the respective inner coating of the plurality of respective inner coatings, wherein the first thickness and the second thickness each comprise a common coating material extending entirely therethrough along a radial direction, wherein the at least one component is configured to be disposed within a flow path of compressed air from a compressor of the engine system, and wherein the respective outer coating of the plurality of respective outer coatings comprises one or more layers each having a thickness of 1 mm to 10 mm to define the first thickness of the respective outer coating. 
 
     
     
       11. The fuel supply system of  claim 10 , wherein the plurality of components comprises a first component and a second component, wherein the first component comprises a first fuel conduit, a first fuel nozzle, a first check valve, a first three-way valve, or a first mixing valve, and the second component comprises a second fuel conduit, a second fuel nozzle, a second check valve, a second three-way valve, or a second mixing valve. 
     
     
       12. The fuel supply system of  claim 10 , excluding a recirculation system or a purging system, or any combination thereof. 
     
     
       13. The fuel supply system of  claim 10 , wherein the one or more layers of the respective outer coating of the plurality of respective outer coatings comprises a plurality of layers of the common coating material that define the first thickness. 
     
     
       14. The fuel supply system of  claim 10 , wherein the at least one component is configured to be disposed within a compressor discharge casing, and wherein the flow path of compressed air extends through the compressor discharge casing. 
     
     
       15. A method comprising:
 applying an inner coating to an inner surface of a component configured to transport fuel to a combustor of an engine system, wherein the component is made of a metal, wherein the component is configured to be disposed within a flow path of compressed air from a compressor of the engine system, and wherein the inner coating comprises a first thickness and is configured to reduce catalytic coke formation in an interior of the component by forming a physical barrier between the inner surface and the fuel; and 
 applying an outer coating to an outer surface of the component, wherein the outer coating comprises a second thickness and is configured to thermally insulate the interior of the component from a heated environment associated with the compressed air to reduce non-catalytic coke formation in the interior, wherein the first thickness is less than the second thickness, wherein the first thickness and the second thickness each comprise a common coating material extending entirely therethrough along a radial direction, and wherein the outer coating comprises one or more layers each having a thickness of 1 mm to 10 mm to define the second thickness of the outer coating. 
 
     
     
       16. The method of  claim 15 , wherein the one or more layers comprise a plurality of layers of the common coating material, wherein the plurality of layers collectively define the second thickness. 
     
     
       17. The method of  claim 15 , wherein the outer coating and the inner coating are applied by a common device. 
     
     
       18. The method of  claim 15 , comprising assembling a fuel supply system from the component having the inner coating and the outer coating, wherein the outer coating is configured to maintain the interior of the component below a thermal degradation temperature of the fuel. 
     
     
       19. The method of  claim 18 , wherein the fuel supply system comprises a plurality of additional components, and each additional component of the plurality of additional components comprises the inner coating on a respective inner surface of the respective additional component and the outer coating on a respective outer surface of the respective additional component. 
     
     
       20. The method of  claim 15 , wherein the one or more layers comprise a plurality of layers, wherein applying the outer coating to the outer surface comprises applying the plurality of layers that form the outer coating with an air plasma spray device, and wherein applying the plurality of layers comprises:
 ionizing an inert gas via an electric current to form a plasma; 
 transferring thermal energy from the plasma to a coating material to form a heated coating material; 
 impinging a first amount of the heated coating material on the outer surface to form a first layer of the plurality of layers; and 
 impinging a second amount of the heated coated material on the first layer of the plurality of layers to form the outer coating.